Tiêu chuẩn iso 00362 1 2007

INTERNATIONAL
STANDARD

ISO
362-1
First edition
2007-07-01

Measurement of noise emitted by
accelerating road vehicles — Engineering
method —
Part 1:
M and N categories
Mesurage du bruit émis par les véhicules routiers en accélération —
Méthode d'expertise —
Partie 1: Catégories M et N

Reference number
ISO 362-1:2007(E)

© ISO 2007


ISO 362-1:2007(E)

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ii

© ISO 2007 – All rights reserved


ISO 362-1:2007(E)

Contents

Page

Foreword............................................................................................................................................................ iv
Introduction ........................................................................................................................................................ v

1

Scope ..................................................................................................................................................... 1

2

Normative references ........................................................................................................................... 1

3

Terms and definitions........................................................................................................................... 2

4

Symbols and abbreviated terms ......................................................................................................... 7

5
5.1
5.2
5.3
5.4
5.5

Specification of the acceleration for vehicles of categories M1 and M2 having a maximum
authorized mass not exceeding 3 500 kg, and of category N1 ........................................................ 9
General................................................................................................................................................... 9
Calculation of acceleration .................................................................................................................. 9
Calculation of the target acceleration............................................................................................... 10
Calculation of the reference acceleration ........................................................................................ 10
Partial power factor kP ........................................................................................................................ 11

6
6.1
6.2
6.3

Instrumentation................................................................................................................................... 11
Instruments for acoustical measurement ........................................................................................ 11
Instrumentation for speed measurements ....................................................................................... 11
Meteorological instrumentation ........................................................................................................ 12

7
7.1
7.2
7.3

Acoustical environment, meteorological conditions and background noise .............................. 12
Test site ............................................................................................................................................... 12
Meteorological conditions ................................................................................................................. 13
Background noise............................................................................................................................... 13

8
8.1
8.2
8.3
8.4
8.5

Test procedures .................................................................................................................................. 14
Microphone positions......................................................................................................................... 14

Conditions of the vehicle ................................................................................................................... 14
Operating conditions.......................................................................................................................... 17
Measurement readings and reported values ................................................................................... 20
Measurement uncertainty .................................................................................................................. 22

9

Test report ........................................................................................................................................... 22

Annex A (informative) Technical background for development of vehicle noise test procedure
based on in-use operation in urban conditions .............................................................................. 24
Annex B (informative) Measurement uncertainty — Framework for analysis according to
ISO Guide 98 (GUM)............................................................................................................................ 44
Annex C (informative) Flowchart of the procedure for categories M1 and M2 having a maximum
authorized mass not exceeding 3 500 kg, and category N1........................................................... 47
Annex D (informative) Flowchart for vehicles of category M2 having a maximum authorized mass
exceeding 3 500 kg, and categories M3, N2 and N3........................................................................ 51
Annex E (informative) Indoor test operation ................................................................................................. 52
Bibliography ..................................................................................................................................................... 55

© ISO 2007 – All rights reserved

iii


ISO 362-1:2007(E)

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO

technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 362-1 was prepared by Technical Committee ISO/TC 43, Acoustics, Subcommittee SC 1, Noise.
This first edition of ISO 362-1, together with ISO 362-2, cancels and replaces ISO 362:1998 and
ISO 7188:1994, which have been technically revised.
ISO 362 consists of the following parts, under the general title Measurement of noise emitted by accelerating
road vehicles — Engineering method:
⎯

Part 1: M and N categories

⎯

Part 2: L category

iv

© ISO 2007 – All rights reserved


ISO 362-1:2007(E)

Introduction
An extensive review was conducted of actual in-use vehicle operations, beginning with data from the TUV
Automotive study in the early 1990s, and continuing with data developed through other committee members
from 1996 through 2000. It includes nearly 100 vehicles operated on a variety of urban roads in Europe and
Asia. The primary focus of the in-use measurements was to determine how vehicles are driven with a variety
of vehicles, driving behaviours and traffic situations. The in-use behaviour determined from these studies was
successfully correlated to urban traffic use in the United States by evaluation of the fuel economy test cycles used
by the United States Environmental Protection Agency (USEPA). The resulting test specifications are therefore
valid for all global urban use conditions.
The procedure defined here provides a measure of the sound pressure level from vehicles under controlled
and repeatable conditions. The definitions have been made according to the needs of vehicle categories. In
cases of vehicles other than very heavy trucks and buses, the working group found that attempts to conduct a
partial load test as in actual use resulted in considerable run-to-run variability that significantly interfered with
the repeatability and reproducibility of the test cycle. Therefore, two primary operating conditions (i.e. a
wide-open-throttle acceleration phase, and a constant speed phase) were used to guarantee simplicity. The
combination was found to be equivalent to the partial throttle and partial power (engine load) actually used.
As a further consequence of the investigation of the needs for an efficient test, it was decided to design a test
which is independent of vehicle design and therefore safe and adaptable for future technologies, as well as for
future traffic conditions. The test guarantees an excitation of all relevant noise sources, and the final test result
will reflect a combination of these sources as a compromise between normal urban use and “worst case”.
In 2004, the given test for M and N category vehicles was evaluated for technical accuracy and practical
considerations by test programmes carried out by the Japan Automobile Standards Internationalization Center
(JASIC), the European Automotive Manufacturers Association (ACEA), and the Society of Automotive
Engineers, Inc. (SAE) in the United States. Over 180 vehicles were included in these tests. The reports of
these test programmes were considered prior to preparation of this part of ISO 362.
This part of ISO 362 was developed following demands for a new test procedure:
⎯

“The test procedure (ISO 362) doesn't reflect realistic driving conditions” (1996 EU Green Paper).

⎯

“In the case of motor vehicles, other factors are also important such as the dominance of tyre noise above
quite low speeds (50 km/h)” (1996 EU Green Paper).

⎯

“A new measurement procedure should require that the major noise sources of a vehicle be measured”
(2001 Noise Emission of Road Vehicles – I-INCE).

© ISO 2007 – All rights reserved

v



INTERNATIONAL STANDARD

ISO 362-1:2007(E)

Measurement of noise emitted by accelerating road vehicles —
Engineering method —
Part 1:
M and N categories

1

Scope

This part of ISO 362 specifies an engineering method for measuring the noise emitted by road vehicles of

categories M and N under typical urban traffic conditions. It excludes vehicles of category L1 and L2, which
are covered by ISO 9645, and vehicles of category L3, L4 and L5 covered by ISO 362-2.
The specifications are intended to reproduce the level of noise generated by the principal noise sources
during normal driving in urban traffic (see Annex A).
The method is designed to meet the requirements of simplicity as far as they are consistent with
reproducibility of results under the operating conditions of the vehicle.
The test method requires an acoustical environment that is only obtained in an extensive open space. Such
conditions are usually provided for
⎯

type approval measurements of a vehicle,

⎯

measurements at the manufacturing stage, and

⎯

measurements at official testing stations.

NOTE 1
The results obtained by this method give an objective measure of the noise emitted under the specified
conditions of test. It is necessary to consider the fact that the subjective appraisal of the noise annoyance of different
classes of motor vehicles is not simply related to the indications of a sound measurement system. As annoyance is
strongly related to personal human perception, physiological human conditions, culture and environmental conditions,
there is a large variation and it is therefore not useful as a parameter to describe a specific vehicle condition.
NOTE 2
Spot checks of vehicles chosen at random are rarely made in an ideal acoustical environment. If
measurements are carried out on the road in an acoustical environment which does not fulfil the requirements stated in
this International Standard, the results obtained can deviate appreciably from the results obtained using the specified

conditions.

2

Normative references

The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 1176:1990, Road vehicles — Masses — Vocabulary and codes
ISO 2416:1992, Passenger cars — Mass distribution
ISO 5725:1994 (all parts), Accuracy (trueness and precision) of measurement methods and results

© ISO 2007 – All rights reserved

1


ISO 362-1:2007(E)

ISO 10844:1994, Acoustics — Specification of test tracks for the purpose of measuring noise emitted by road
vehicles
ISO Guide 98:1995, Guide to the expression of uncertainty in measurement (GUM)
IEC 60942:2003, Electroacoustics — Sound calibrators
IEC 61672-1:2002, Electroacoustics — Sound level meters — Part 1: Specifications

3

Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 1176, ISO 2416 and the following
apply.
3.1

Vehicle mass

3.1.1
kerb mass
complete shipping mass of a vehicle fitted with all equipment necessary for normal operation plus the mass of
the following elements for M1, N1 and M2 having a maximum authorized mass not exceeding 3 500 kg:
⎯

lubricants, coolant (if needed), washer fluid;

⎯

fuel (tank filled to at least 90 % of the capacity specified by the manufacturer);

⎯

other equipment if included as basic parts for the vehicle, such as spare wheel(s), wheel chocks, fire
extinguisher(s), spare parts and tool kit

NOTE
The definition of kerb mass may vary from country to country, but in this part of ISO 362 it refers to the
definition contained in ISO 1176.

3.1.2
maximum authorized mass
kerb mass plus the maximum allowable payload

3.1.3
target mass
actual vehicle mass used during test as determined by Table 3
NOTE

Test mass for N2 and N3 vehicles can be lower than the target mass due to axle-loading limitations.

3.1.4
test mass
actual vehicle mass used during test as determined by Table 3
NOTE

Test mass for N2 and N3 vehicles can be lower than the target mass due to axle-loading limitations.

3.1.5
unladen vehicle mass
nominal mass of a complete N2, N3 or M2 vehicle having a maximum authorized mass greater than 3 500 kg,
or an M3 vehicle as determined by the following conditions:
a)

mass of the vehicle includes the bodywork and all factory-fitted equipment, electrical and auxiliary
equipment for normal operation of the vehicle, including liquids, tools, fire extinguisher, standard spare
parts, chocks and spare wheel, if fitted;

b)

the fuel tank is filled to at least 90 % of rated capacity and the other liquid-containing systems (except
those for used water) are filled to 100 % of the capacity specified by the manufacturer

2

© ISO 2007 – All rights reserved


ISO 362-1:2007(E)

3.1.6
driver mass
nominal mass of a driver
3.1.7
mass in running order
nominal mass of an N2, N3 or M2 vehicle having a maximum authorized mass greater than 3 500 kg, or an
M3 vehicle as determined by the following conditions:
a)

the mass is taken as the sum of the unladen vehicle mass and the driver's mass;

b)

in the case of category M2 and M3 vehicles that include seating positions for additional crewmembers,
their mass is incorporated in the same way and equal to that of the driver

NOTE

The driver's mass is calculated in accordance with ISO 2416.

3.1.8
maximum axle (group of axles) capacity
permissible mass corresponding to the maximum mass to be carried by the axle (group of axles) as defined
by the vehicle manufacturer, not exceeding the axle manufacturer's specifications

3.1.9
unladen axle (group of axles) load
actual mass carried by the axle (group of axles) in an unladen condition
NOTE

The unladen vehicle mass is equal to the sum of the unladen axles (group of axles) load.

3.1.10
extra loading
mass which is to be added to the unladen vehicle mass
3.1.11
laden axle (group of axles) load
actual mass carried by the axle (group of axles) in a laden condition
3.2
power-to-mass ratio index
PMR
dimensionless quantity used for the calculation of acceleration according to the equation

PMR =

Pn
× 1 000
mt

(1)

where
Pn is the numerical value of engine power, expressed in kilowatts;
mt

is the numerical value of the test mass, expressed in kilograms

3.3
rated engine speed
S
engine speed at which the engine develops its rated maximum net power as stated by the manufacturer
NOTE 1
If the rated maximum net power is reached at several engine speeds, S used in this part of ISO 362 is the
highest engine speed at which the rated maximum net power is reached.
NOTE 2
ISO 80000-3 defines this term as “rated engine rotational frequency”. The term “rated engine speed” was
retained due to its common understanding by practitioners and its use in government regulations.

© ISO 2007 – All rights reserved

3


ISO 362-1:2007(E)

3.4

Vehicle categories

3.4.1
category L
motor vehicles with fewer than four wheels
NOTE
United Nations Economic Commission for Europe (UNECE) document TRANS/WP.29/78/Rev.1/Amend.4
(26 April 2005) extended the L category to four-wheeled vehicles as defined by L6 and L7.

3.4.1.1
category L1 and L2
mopeds
NOTE

See ISO 9645 for further details.

3.4.1.2
category L3
two-wheeled motor vehicles with an engine cylinder capacity greater than 50 cm3 or maximum speed greater
than 50 km/h
3.4.1.3
category L4
three-wheeled motor vehicles with an engine cylinder capacity greater than 50 cm3 or maximum speed
greater than 50 km/h, the wheels being attached asymmetrically along the longitudinal vehicle axis
3.4.1.4
category L5
three-wheeled motor vehicles with an engine cylinder capacity greater than 50 cm3 or maximum speed
greater than 50 km/h, having a gross vehicle mass rating not exceeding 1 000 kg and wheels attached
symmetrically along the longitudinal vehicle axis
3.4.1.5
category L6
four-wheeled vehicles whose unladen mass is not more than 350 kg, not including the mass of the batteries in
the case of electric vehicles, whose maximum design speed is not more than 45 km/h, and whose engine
cylinder capacity does not exceed 50 cm3 for spark (positive) ignition engines, or whose maximum net power
output does not exceed 4 kW in the case of other internal combustion engines, or whose maximum
continuous rated power does not exceed 4 kW in the case of electric engines
3.4.1.6
category L7

four-wheeled vehicles, other than those classified as category L6, whose unladen mass is not more than
400 kg (550 kg for vehicles intended for carrying goods), not including the mass of the batteries in the case of
electric vehicles, and whose maximum continuous rated power does not exceed 15 kW
3.4.2
category M
power-driven vehicles having at least four wheels and used for the carriage of passengers
3.4.2.1
category M1
vehicles used for the carriage of passengers and comprising no more than eight seats in addition to the
driver's seat
3.4.2.2
category M2
vehicles used for the carriage of passengers and comprising more than eight seats in addition to the driver's
seat and having a maximum mass not exceeding 5 000 kg
NOTE
ISO 362.

4

In this definition, “maximum mass” is equivalent to “maximum authorized mass” used elsewhere in this part of

© ISO 2007 – All rights reserved


ISO 362-1:2007(E)

3.4.2.3
category M3
vehicles used for the carriage of passengers and comprising more than eight seats in addition to the driver's
seat and having a maximum mass exceeding 5 000 kg

NOTE
ISO 362.

In this definition, “maximum mass” is equivalent to “maximum authorized mass” used elsewhere in this part of

3.4.3
category N
power-driven vehicles having at least four wheels and used for the carriage of goods
3.4.3.1
category N1
vehicles used for the carriage of goods and having a maximum authorized mass not exceeding 3 500 kg
3.4.3.2
category N2
vehicles used for the carriage of goods and having a maximum authorized mass exceeding 3 500 kg but not
exceeding 12 000 kg
3.4.3.3
category N3
vehicles used for the carriage of goods and having a maximum authorized mass exceeding 12 000 kg
3.5
reference point
point depending on the design and category of the vehicle
3.5.1
reference point for category M1 and N1 vehicles
point on the vehicle as follows:
⎯

for front engine vehicles, it is the front end of the vehicle;

⎯

for mid-engine vehicles, it is the centre of the vehicle;

⎯

for rear engine vehicles, it is the rear end of the vehicle

3.5.2
reference point for category M2, M3, N2, and N3 vehicles
point on the vehicle as follows:
⎯

for front engine vehicles, it is the front end of the vehicle;

⎯

for all other vehicles, it is the border of the engine closest to the front of the vehicle

3.6
target acceleration
acceleration at a partial throttle condition in urban traffic, derived from statistical investigations
NOTE

Refer to Annex A for more detailed explanations.

3.7
reference acceleration
required acceleration during the acceleration test on the test track
NOTE

Refer to Annex A for more detailed explanations.

© ISO 2007 – All rights reserved

5


ISO 362-1:2007(E)

3.8
gear ratio weighting factor
k
dimensionless quantity used to combine the test results of two gear ratios for the acceleration test and the
constant-speed test
3.9
partial power factor
kP
dimensionless quantity used for the weighted combination of the test results of the acceleration test and the
constant-speed test for vehicles of categories M1, N1 and M2 having a maximum authorized mass not
exceeding 3 500 kg
NOTE

Refer to Annex A for more detailed explanations.

3.10
pre-acceleration
application of acceleration control device prior to the position AA' for the purpose of achieving stable
acceleration between AA' and BB'
NOTE

See Figure 1 for additional details.

3.11
locked gear ratio
control of transmission such that the transmission gear cannot change during a test
3.12
engine
power source without detachable accessories
3.13
test track length
l10
length of test track used in the calculation of acceleration from points PP' to BB'
3.14
test track length
l20
length of test track used in the calculation of acceleration from points AA' to BB'

6

© ISO 2007 – All rights reserved


ISO 362-1:2007(E)

4

Symbols and abbreviated terms

Table 1 lists the symbols used in this document and the clause where they are used for the first time.
Table 1 — Symbols and abbreviated terms used, and corresponding clauses
Symbol

Unit

Clause

Explanation

AA'

—

3.10

line perpendicular to vehicle travel which indicates beginning of zone in
which to record sound pressure level during test

ai

m/s2

A.2.6

partial throttle acceleration in gear i

amax

m/s2

A.2.2.3

maximum acceleration during an acceleration phase measured in in-use
studies

amax 90

m/s2

A.2.3.1

90th percentile of maximum acceleration during an acceleration phase
measured in in-use studies

awot

m/s2

A.2.2.1

in-use acceleration measured in urban traffic for a specific vehicle

awot 50

m/s2

A.2.8.1

acceleration at 90th percentile of noise emission and 50 km/h vehicle
velocity for a specific vehicle

awot i

m/s2

5.1

acceleration at wide-open-throttle in gear i

awot (i + 1)

m/s2

5.1

acceleration at wide-open-throttle in gear (i + 1)

awot test

m/s2

5.1

acceleration at wide-open throttle in single gear test cases

awot ref

m/s2

5.4

reference acceleration for the wide-open-throttle test

aurban

m/s2

5.3

target acceleration representing urban traffic acceleration

BB'

—

3.10

line perpendicular to vehicle travel which indicates end of zone in which to
record sound pressure level during test

CC'

—

8.1

line of vehicle travel through test surface defined in ISO 10844

δ1 − δ7

dB

B.2

input quantities to allow for any uncertainty

gear i

—

8.3.1.3.2

first of two gear ratios for use in the vehicle test

gear (i + 1)

—

8.3.1.3.2

second of two gear ratios, with an engine speed lower than gear ratio i

j

—

kP

—

3.9

partial power factor

k

—

3.8

gear ratio weighting factor

kn

—

A.2.8.1

lref

m

5.1

reference length

lveh

m

5.1

length of vehicle

l10

m

3.13

length of test section for calculation of acceleration from PP' to BB'

l20

m

3.14

length of test section for calculation of acceleration from AA' to BB'

Lcrs i

dB

8.4.3.2

vehicle sound pressure level at constant speed test for gear i

Lcrs (i + 1)

dB

8.4.3.2

vehicle sound pressure level at constant speed test for gear (i + 1)

Lcrs rep

dB

8.4.3.2

reported vehicle sound pressure level at constant speed test

Lwot i

dB

8.4.3.2

vehicle sound pressure level at wide-open-throttle test for gear i

Lwot (i + 1)

dB

8.4.3.2

vehicle sound pressure level at wide-open-throttle test for gear (i + 1)

Lwot rep

dB

8.4.3.2

reported vehicle sound pressure level at wide-open-throttle

© ISO 2007 – All rights reserved

index for single test run within overall acceleration or constant speed test
series i or (i + 1)

interpolation factor between gears

7


ISO 362-1:2007(E)

Table 1 — (continued)
Symbol

Unit

Clause

Lurban

dB

8.4.3.2

reported vehicle sound pressure level representing urban operation

mfa load unladen

kg

8.2.2.1

unladen front axle load

mac ra max

kg

8.2.2.1

maximum rear axle capacity

mra load unladen

kg

8.2.2.1

unladen rear axle load

md

kg

8.2.2.1

mass of driver

mkerb

kg

8.2.2.1

kerb mass of the vehicle

mfa load laden

kg

8.2.2.2.2

laden front axle load

mra load laden

kg

8.2.2.2.2

laden rear axle load

mref

kg

8.2.2.1

kerb mass + 75 kg for the driver (75 kg ± 5 kg in the case of category L)

mro

kg

8.2.2.1

mass in running order

mt

kg

3.2

mtarget

kg

8.2.2.1

target mass of the vehicle

munladen

kg

8.2.2.1

unladen vehicle mass

mxload

kg

8.2.2.1

extra loading

n

1/min

A.2.4

nPP'

1/min

9

engine rotational speed of the vehicle when the reference point passes
PP'

nBB'

1/min

8.3.2.2.1

engine rotational speed of the vehicle, when the reference point passes
BB'

(n/S)a 90

—

A.2.8.1

dimensionless engine rotational speed ratio at 90th percentile acceleration

(n/S)L 90

—

A.2.6

dimensionless engine rotational speed ratio at 90th percentile noise
emission

(n/S)i

—

A.2.8.1

dimensionless engine rotational speed ratio at maximum acceleration of i
gear

(n/S)(i + 1)

—

A.2.8.1

dimensionless engine rotational speed ratio at maximum acceleration of
(i + 1) gear

PMR

—

3.2

power-to-mass ratio index to be used for calculations

Pn

kW

3.2

rated engine power (see ISO 1585)

PP'

—

3.13

line perpendicular to
microphones

S

1/min

3.3

rated engine rotational speed in revs per minute, synonymous with the
engine rotational speed at maximum power

vAA'

km/h

5.2.1

vehicle velocity when reference point passes line AA' (see 5.1 for
definition of reference point)

vBB'

km/h

5.2.1

vehicle velocity when reference point or rear of vehicle passes line BB'
(see 5.1 for definition of reference point)

vPP'

km/h

5.2.2

vehicle velocity when reference point passes line PP' (see 5.1 for
definition of reference point)

vtest

km/h

8.3.1.2

target vehicle test velocity

va max 50

km/h

A.2.3.1

50th percentile vehicle velocity at maximum acceleration during an

acceleration phase measured in in-use studies

va max 90

km/h

A.2.3.1

90th percentile vehicle velocity at maximum acceleration during an
acceleration phase measured in in-use studies

8

Explanation

test mass of the vehicle

engine rotational speed of the vehicle

vehicle travel

which

indicates location

of

© ISO 2007 – All rights reserved

ISO 362-1:2007(E)

5 Specification of the acceleration for vehicles of categories M1 and M2 having a
maximum authorized mass not exceeding 3 500 kg, and of category N1
5.1

General

All accelerations are calculated using different speeds of the vehicle on the test track. The formulas given in
5.2 are used for the calculation of awot i, awot (i + 1) and awot test. The speed either at AA' (vAA') or PP' (vPP') is
defined by the vehicle speed when the reference point passes AA' or PP'. The speed at BB' (vBB′) is defined
when the rear of the vehicle passes BB'. The method used for determination of the acceleration shall be
indicated in the test report
Due to the definition of the reference point for the vehicle, the length of the vehicle is considered to be
different in Equations (2) and (3). If the reference point is the front of the vehicle, lref = lveh, i.e. the length of
vehicle; if the reference point is the midpoint of the vehicle, lref = 0,5 lveh (i.e. 0,5 times the length of vehicle); if
the reference point is the rear of the vehicle, lref = 0.
The dimensions of the test track are used in the calculation of acceleration. These dimensions are defined as
follows: l20 = 20 m, l10 = 10 m.
Due to the large variety of technologies, it is necessary to consider different modes of calculation. New
technologies (such as continuously variable transmission) and older technologies (such as automatic
transmission) which have no electronic control, require a more specific treatment for a proper determination of
the acceleration. The given possibilities for calculation of the acceleration shall cover these needs.

5.2

Calculation of acceleration

5.2.1 Calculation procedure for vehicles with manual transmission, automatic transmission, adaptive
transmission and continuously variable transmission (CVT) tested with locked gear ratios

The value of awot test used in the determination of gear selection shall be the average of the four awot test, j
values during each valid measurement run.
Calculate awot test, j using the equation:

( vBB', j / 3,6 ) − ( v AA', j / 3,6 )
=
2

a wot test, j

2

2 ( l 20 + l ref )

(2)

where
awot test, j

is the numerical value of the acceleration, expressed in metres per second squared;

vBB', j, vAA', j are numerical values of the velocity, expressed in kilometres per hour;
l20, lref

are numerical values of the length, expressed in metres.

Pre-acceleration may be used.
5.2.2 Calculation procedure for vehicles with automatic transmission, adaptive transmission and
CVT tested with non-locked gear ratios

The value of awot test used in the determination of gear selection shall be the average of the four awot test, j
values during each valid measurement run.
If the devices or measures described in 8.3.1.3.3 are used to control transmission operation for the purpose of
achieving test requirements, calculate awot test, j using Equation (2).
Pre-acceleration may be used.

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ISO 362-1:2007(E)

If the devices or measures described in 8.3.1.3.3 are not used, calculate awot test, j using Equation (3):

a wot test, j =

( vBB' / 3,6 ) 2 − ( vPP' / 3,6 ) 2
2 ( l10 + l ref )

(3)

where
awot test, j is the numerical value of the acceleration, expressed in metres per second squared;
vPP', vBB' are numerical values of the velocity, expressed in kilometres per hour;
l10, lref

are numerical values of the length, expressed in metres.

Pre-acceleration shall not be used.

NOTE
It would be useful for these types of vehicles to record the vehicle speeds at AA', PP', and BB' to provide
information for a future revision of this part of ISO 362.

5.3

Calculation of the target acceleration

Calculate aurban using the equation:
aurban = 0,63 lg(PMR) − 0,09

(4)

where
aurban is the numerical value of the acceleration, expressed in metres per second squared;
PMR

5.4

is the dimensionless value of the power-to-mass index.

Calculation of the reference acceleration

Calculate awot ref using the equations:
awot ref = 1,59 lg(PMR) − 1,41 for 25 u PMR

(5)

awot ref = aurban = 0,63 lg(PMR) − 0,09 for 25 > PMR

(6)

or

where
awot ref is the numerical value of the reference acceleration, expressed in metres per second squared;
aurban is the numerical value of the acceleration relative to urban traffic, expressed in metres per second
squared;
PMR

is the dimensionless value of the power-to-mass index.

NOTE
Calculations of awot ref and aurban for a specific vehicle are based on statistical analyses of in-use vehicle data.
As such, this is not strictly a calculation of acceleration based on the independent non-dimensional variable PMR, since
this is used as a function to identify the appropriate target acceleration.

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ISO 362-1:2007(E)

5.5

Partial power factor kP

Partial power factor kP is:
kP = 1 − (aurban/awot test)

(7)

In cases other than a single gear test, awot ref shall be used instead of awot test, as defined in 8.4.3.2.

6

Instrumentation

6.1
6.1.1

Instruments for acoustical measurement
General

The apparatus used for measuring the sound pressure level shall be a sound level meter or equivalent
measurement system meeting the requirements of Class 1 instruments (inclusive of the recommended
windscreen, if used). These requirements are described in IEC 61672-1.
The entire measurement system shall be checked by means of a sound calibrator that fulfils the requirements
of Class 1 sound calibrators according to IEC 60942.
Measurements shall be carried out using the time weighting “F” of the acoustic measurement instrument and
the “A” frequency weighting curve also described in IEC 61672-1. When using a system that includes periodic
monitoring of the A-weighted sound pressure level, a reading should be made at a time interval not greater
than 30 ms.
The instruments shall be maintained and calibrated in accordance with the instructions of the instrument
manufacturer.
6.1.2

Calibration

At the beginning and at the end of every measurement session, the entire acoustic measurement system shall
be checked by means of a sound calibrator as described in 6.1.1. Without any further adjustment, the
difference between the readings shall be less than or equal to 0,5 dB. If this value is exceeded, the results of
the measurements obtained after the previous satisfactory check shall be discarded.
6.1.3

Compliance with requirements

Compliance of the sound calibrator with the requirements of IEC 60942 shall be verified once a year.
Compliance of the instrumentation system with the requirements of IEC 61672-1 shall be verified at least
every 2 years. All compliance testing shall be conducted by a laboratory which is authorized to perform
calibrations traceable to the appropriate standards.

6.2

Instrumentation for speed measurements

The rotational speed of the engine shall be measured with an instrument meeting specification limits of at
least ± 2 % at the engine speeds required for the measurements being performed.
The road speed of the vehicle shall be measured with instruments meeting specification limits of at least
± 0,5 km/h when using continuous measuring devices.
If testing uses independent measurements of speed, this instrumentation shall meet specification limits of at
least ± 0,2 km/h.
NOTE
Independent measurements of speed are when two or more separate devices will determine the vAA', vBB' and
vPP' values. A continuous measuring device will determine all required speed information with one device.

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ISO 362-1:2007(E)

6.3

Meteorological instrumentation

The meteorological instrumentation used to monitor the environmental conditions during the test shall meet
the following specifications:
⎯

at least ± 1 °C for a temperature measuring device;

⎯

at least ± 1,0 m/s for a wind speed measuring device;

⎯

at least ± 5 hPa for a barometric pressure measuring device;

⎯

at least ± 5 % for a relative humidity measuring device.

7

Acoustical environment, meteorological conditions and background noise

7.1

Test site

The test site shall be substantially level. The test track construction and surface shall meet the requirements
of ISO 10844. The test site dimensions are shown in Figure 1.
NOTE
The symbols in Figure 1 are directly copied from ISO 10844 and are not necessarily consistent with the
symbols in this part of ISO 362.

Within a radius of 50 m around the centre of the track, the space shall be free of large reflecting objects such
as fences, rocks, bridges or buildings. The test track and the surface of the site shall be dry and free from
absorbing materials such as powdery snow or loose debris.
In the vicinity of the microphone, there shall be no obstacle that could influence the acoustical field and no
person shall remain between the microphone and the noise source. The meter observer shall be positioned so
as not to influence the meter reading.
NOTE

12

Buildings outside the 50 m radius can have significant influence if their reflection focuses on the test track.

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ISO 362-1:2007(E)

Dimensions in metres

Key

minimum area covered with test road surface, i.e test area
microphone positions (height 1,2 m)
NOTE

Shaded area (“test area”) is the minimum area to be covered with a surface complying with ISO 10844.

Figure 1 — Test site dimensions

7.2

Meteorological conditions

The meteorological instrumentation shall deliver data representative of the test site, and shall be positioned
adjacent to the test area at a height representative of the height of the measuring microphone.
The measurements shall be made when the ambient air temperature is within the range from 5 °C to 40 °C.
The tests shall not be carried out if the wind speed, including gusts, at microphone height exceeds 5 m/s
during the sound measurement interval.
A value representative of temperature, wind speed and direction, relative humidity and barometric pressure
shall be recorded during the sound measurement interval.
NOTE

7.3

Refer to Annex B for the effects of temperature and other factors.

Background noise

Any sound peak which appears to be unrelated to the characteristics of the general sound level of the vehicle
shall be ignored when taking the readings.
The background noise shall be measured for a duration of 10 s immediately before and after a series of

vehicle tests. The measurements shall be made with the same microphones and microphone locations used
during the test. The maximum A-weighted sound pressure level shall be reported.

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ISO 362-1:2007(E)

The background noise (including any wind noise) shall be at least 10 dB below the A-weighted sound
pressure level produced by the vehicle under test. If the difference between the ambient sound pressure level
and the measured sound pressure level is between 10 dB and 15 dB, in order to calculate the jth test result
the appropriate correction shall be subtracted from the readings on the sound level meter, as given in Table 2.
Table 2 — Correction applied to an individual measured test value
Background sound pressure
level difference to measured
sound pressure level, in dB

10

11

12

13

14

greater than

or equal
to 15

Correction, in dB

0,5

0,4

0,3

0,2

0,1

0,0

8

Test procedures

8.1

Microphone positions

The distance from the microphone positions on the microphone line PP' to the perpendicular reference line
CC' (see Figure 1) on the test track shall be 7,5 m ± 0,05 m.
The microphone shall be located 1,2 m ± 0,02 m above the ground level. The reference direction for free-field
conditions (see IEC 61672-1) shall be horizontal and directed perpendicularly towards the path of the vehicle
line CC'.

8.2

Conditions of the vehicle

8.2.1

General conditions

The vehicle shall be supplied as specified by the vehicle manufacturer.
Before the measurements are started, the vehicle shall be brought to its normal operating conditions.
The variation of results between runs may be reduced if there is a 1-min wait, at idle in neutral, between runs.
8.2.2
8.2.2.1

Test mass of the vehicle
General

Measurements shall be made on vehicles at the test mass mt specified in Table 3.

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ISO 362-1:2007(E)

Table 3 — Test mass, mt
Vehicle category

Vehicle test mass
kg

M1

mt = mref = mkerb + 75 kg. The 75 kg added mass accounts for the mass of the driver according to
ISO 2416.

N1 a, b

mt = mref = mkerb + 75 kg. The 75 kg added mass accounts for the mass of the driver according to
ISO 2416.

N2, N3

mtarget (per kW rated power) = 50 kg. Extra loading, mxload, to reach the target mass, mtarget, of the
vehicle shall be placed above the rear axle.
The sum of the extra loading and the unladen rear axle load, mra load unladen, is limited to 75 % of the
maximum axle capacity, mac ra max, allowed for the rear axle. The target mass shall be achieved with
a tolerance of ± 5 %.
If the centre of gravity of the extra loading cannot be aligned with the centre of the rear axle, the test
mass, mt, of the vehicle shall not exceed the sum of the unladen front axle load, mfa load unladen, and
the unladen rear axle load plus the extra loading and the mass of driver, md.
The test mass for vehicles with more than two axles shall be the same as for a two-axle vehicle.
If the unladen vehicle mass, munladen, of a vehicle with more than two axles is greater than the test
mass for the two-axle vehicle, then this vehicle shall be tested without extra loading.

M2, M3

mt = mro

a

N1 category vehicles may be loaded, at the decision of the vehicle manufacturer, for practical reasons during the test. This practice
is acceptable, however it may lead to a higher level of vehicle noise (typically 1 dB).

b

If load is added to these vehicles during testing, the added payload shall be noted in the test report.

8.2.2.2
8.2.2.2.1

Calculation procedure to determine extra loading of N2 and N3 vehicles only
Calculation of extra loading

The target mass mtarget (per kW rated power) for two-axle vehicles of category N2 and N3 is specified in
Table 3:
mtarget = 50 kg

(8)

To reach the required target mass mtarget for a vehicle to be tested, the unladen vehicle, including the mass of
the driver md, shall be loaded with an extra mass mxload which shall be placed above the rear axle:
mtarget = munladen + md + mxload

(9)

The target mass mtarget shall be achieved with a tolerance of ± 5 %.
The vehicle mass of the test vehicle in the unladen condition munladen is calculated by measuring on a scale

the unladen front axle load mfa load unladen and the unladen rear axle load mra load unladen:
munladen = mfa load unladen + mra load unladen

(10)

By using Equations (9) and (10), the extra loading mxload is calculated as follows:
mxload = mtarget − (md + munladen)

(11)

mxload = mtarget − (md + mfa load unladen + mra load unladen)

(12)

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ISO 362-1:2007(E)

The sum of the extra loading, mxload, and the unladen rear axle load, mra load unladen, is limited to 75 % of the
maximum axle capacity for the rear axle, mac ra max:
0,75 mac ra max W mxload + mra load unladen

(13)

The mxload is limited according to Equation (14):
mxload u 0,75 mac ra max − mra load unladen

(14)

If the calculated extra loading mxload in Equation (12) fulfils Equation (14), then the extra loading is equal to
Equation (12). The test mass mt of the vehicle is equal to
mt = mxload + md + mfa load unladen + mra load unladen

(15)

In this case, the test mass of the vehicle is equal to the target mass
mt = mtarget

(16)

If the calculated extra loading mxload in Equation (12) does not fulfil Equation (14), but rather fulfils
Equation (17)
mxload > 0,75 mac ra max − mra load unladen

(17)

the extra loading mxload shall be equal to
mxload = 0,75 mac ra max − mra load unladen

(18)

and the test mass mt of the vehicle shall be equal to
mt = 0,75 mac ra max + md + mfa load unladen

(19)

In this case, the test mass of the vehicle is lower than the target mass

mt < mtarget
8.2.2.2.2

(20)

Loading considerations if load cannot be aligned with the centre of rear axle

If the centre of gravity of the extra loading mxload cannot be aligned with the centre of the rear axle, the test
mass of the vehicle mt shall not exceed the sum of the unladen front axle load mfa load unladen and the unladen
rear axle load mra load unladen plus the extra loading mxload and the mass of the driver md.
This means that if the actual front and rear axle load are measured on a scale when the extra loading mxload is
placed onto the vehicle and it is aligned with the centre of the rear axle, the test mass of the vehicle minus the
mass of the driver is equal to
mt − md = mfa load laden + mra load laden

(21)

where
mfa load laden = mfa load unladen

(22)

If the centre of gravity of the extra loading cannot be aligned with the centre of the rear axle, Equation (21) is
still fulfilled, but
mfa load laden > mfa load unladen

(23)

because the extra loading has partly distributed its mass to the front axle. In that case, it is not allowed to add
more mass onto the rear axle to compensate for the mass moved to the front axle.

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ISO 362-1:2007(E)

8.2.2.2.3

Test mass for vehicles with more than two axles

If a vehicle with more than two axles is tested, then the test mass of this vehicle shall be the same as the test
mass for the two-axle vehicle.
If the unladen vehicle mass of a vehicle with more than two axles is greater than the test mass for the two-axle
vehicle, then this vehicle shall be tested without extra loading.
8.2.3

Tyre selection and condition

The tyres shall be appropriate for the vehicle and shall be inflated to the pressure recommended by the tyre
manufacturer for the test mass of the vehicle.
For certification and related purposes, additional requirements for the tyres, defined by regulation, are
necessary. The tyres for such a test shall be selected by the vehicle manufacturer, and shall correspond to
one of the tyre sizes and types designated for the vehicle by the vehicle manufacturer. The tyre shall be
commercially available on the market at the same time as the vehicle. The minimum tread depth shall be at
least 80 % of the full tread depth.
NOTE

8.3

The tread depth can have a significant influence on the test result.

Operating conditions

8.3.1 Vehicles of categories M1 and M2 having a maximum authorized mass not exceeding 3 500 kg,
and category N1
8.3.1.1

General conditions

The path of the centreline of the vehicle shall follow line CC' as closely as possible throughout the entire test,
from the approach to line AA' until the rear of the vehicle passes line BB' (see Figure 1). Any trailer that is not
readily separable from the towing vehicle shall be ignored when considering the crossing of the line BB'. If the
vehicle is fitted with more than two-wheel drive, test it in the drive selection that is intended for normal road
use. If the vehicle is fitted with an auxiliary manual transmission or a multi-gear axle, the position used for
normal urban driving shall be used. In all cases, the gear ratios for slow movements, parking or braking, shall
be excluded.
8.3.1.2

Test speed

The test speed vtest shall be 50 km/h ± 1 km/h. The test speed shall be reached when the reference point
according to 3.5 is at line PP'.
8.3.1.3
8.3.1.3.1

Gear ratio selection
General

It is the responsibility of the manufacturer to determine the correct manner of testing to achieve the required
accelerations.
Annex C gives gear selection criteria and test run criteria for categories M1 and M2 having a maximum
authorized mass not exceeding 3 500 kg, and for category N1, in a flowchart form as an aid to test operation.
8.3.1.3.2
Manual transmission, automatic transmissions, adaptive transmissions or transmissions
with continuously variable gear ratios (CVTs) tested with locked gear ratios
The selection of gear ratios for the test depends on the specific acceleration achieved awot, i under full-throttle
condition according to the specification in 5.2.1 in relation to the reference acceleration awot ref required for the
full-throttle acceleration test according to Equation (5) in 5.4.

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ISO 362-1:2007(E)

The following conditions for selection of gear ratios are possible.
a)

If one specific gear ratio gives acceleration in a tolerance band of ± 5 % of the reference acceleration
awot ref, not exceeding 2,0 m/s2, test with that gear ratio.

b)

If none of the gear ratios gives the required acceleration, then choose a gear ratio i, with an acceleration
higher and a gear ratio (i + 1), with an acceleration lower than the reference acceleration awot ref. If the
acceleration value in gear ratio i does not exceed 2,0 m/s2, use both gear ratios for the test. The gear
ratio weighting factor k in relation to the reference acceleration awot ref is calculated by:

k = (awot ref − awot (i + 1))/(awot i − awot (i + 1))

(24)

c)

If the acceleration value of gear ratio i or (i + 1) exceeds 2,0 m/s2, the first gear ratio shall be used that
gives an acceleration below 2,0 m/s2 unless gear ratio (i + 1) provides acceleration less than aurban. The
achieved acceleration awot test during the test shall be used for the calculation of the partial power factor
kP instead of awot ref for tests using one gear.

d)

In the case where gear ratio (i + 1) provides acceleration less than aurban, two gears, i and (i + 1) shall be
used, including the gear i with acceleration exceeding 2,0 m/s2. The gear ratio weighting factor k in
relation to the reference acceleration awot ref is calculated by Equation (24).

If the vehicle has a transmission in which there is only one selection for the gear ratio, the full-throttle test is
carried out in this vehicle gear selection. The achieved acceleration awot test is then used for the calculation of
the partial power factor kP (see 3.9) instead of awot ref.
If rated engine speed is exceeded in a gear ratio before the vehicle passes BB', the next higher gear shall be
used.
8.3.1.3.3
Automatic transmission, adaptive transmissions and transmissions with variable gear
ratios tested with non-locked gear ratios
The gear selector position for full automatic operation shall be used.
The acceleration awot test shall be calculated by Equation (2) or (3) as specified in 5.2.
The test may then include a gear change to a lower range and a higher acceleration. A gear change to a
higher range and a lower acceleration is not allowed. In any case, a gear shifting to a gear ratio which is
typically not used at the specified condition in urban traffic shall be avoided.

Therefore, it is permitted to establish and use electronic or mechanical devices, including alternative gear
selector positions, to prevent a downshift to a gear ratio which is typically not used at the specified test
condition in urban traffic.
The achieved acceleration awot test shall be greater than or equal to aurban.
If possible, the manufacturer shall take measures to avoid an acceleration value awot test greater than 2,0 m/s2.
The achieved acceleration awot test is then used for the calculation of the partial power factor kP (see 3.9)
instead of awot ref.
8.3.1.4

Acceleration test

The acceleration test shall be carried out in all gear ratios specified for the vehicle according to 8.3.1.3 with
the test speed specified in 8.3.1.2.
When the front of the vehicle reaches the AA', the acceleration control unit shall be fully engaged and held
fully engaged until the rear of the vehicle reaches BB'. The acceleration control unit shall then be released.
Pre-acceleration may be used if acceleration is delayed beyond AA'. The location of the start of the
acceleration shall be reported.
The calculated acceleration awot test shall be noted to the second digit after the decimal place.

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ISO 362-1:2007(E)

8.3.1.5

Constant-speed test

The constant-speed test is not required for vehicles with a PMR u 25.
For vehicles with transmissions specified in 8.3.1.3.2, the constant-speed test shall be carried out with the
same gears specified for the acceleration test. For vehicles with transmissions specified in 8.3.1.3.3, the gear
selector position for full automatic operation shall be used. If the gear is locked for the acceleration test, the
same gear shall be locked for the constant-speed test.
During the constant-speed test, the acceleration control unit shall be positioned to maintain a constant speed
between AA' and BB' as specified in 8.3.1.2.
8.3.2 Vehicles of category M2 having a maximum authorized mass exceeding 3 500 kg, and
categories M3, N2 and N3
8.3.2.1

General conditions

The path of the centreline of the vehicle shall follow line CC' as closely as possible throughout the entire test,
from the approach to line AA' until the rear of the vehicle passes line BB' (see Figure 1) and the reference
point is 5 m behind line BB'. The test shall be conducted without a trailer or semi-trailer. If a trailer is not
readily separable from the towing vehicle, it shall be ignored when considering the crossing of line BB'. If the
vehicle incorporates equipment such as a concrete mixer, a compressor, etc., this equipment shall not be in
operation during the test. The test mass of the vehicle including the test payload shall be according to Table 3.
Annex D gives gear selection criteria and test run criteria for category M2 having a maximum authorized mass
exceeding 3 500 kg, and for categories M3, N2 and N3, in a flowchart form as an aid to test operation.
8.3.2.2

Target conditions

8.3.2.2.1
Vehicles of category M2 having a maximum authorized mass exceeding 3 500 kg, and
category N2
When the reference point passes BB', the engine rotational speed nBB' shall be between 70 % and 74 % of the
speed S. The vehicle test speed vtest shall be 35 km/h ± 5 km/h.

8.3.2.2.2

Categories M3 and N3

When the reference point passes BB', the engine rotational speed nBB' shall be between 85 % and 89 % of
speed S. The vehicle test speed vtest shall be 35 km/h ± 5 km/h.
8.3.2.3
8.3.2.3.1

Gear selection
General

It is the responsibility of the manufacturer to determine the correct manner of testing to achieve the required
conditions.
8.3.2.3.2

Manual transmission

Stable acceleration conditions shall be ensured. The gear choice is determined by the target conditions.
If more than one gear fulfils the target conditions, take the gear which gives velocity closest to 35 km/h. If no
single transmission gear fulfils the target condition for vtest, then two gears shall be tested, one above and one
below vtest. The target engine speed shall be reached in any condition.
A stable acceleration condition shall be ensured. If a stable acceleration cannot be ensured in a gear, this
gear shall be disregarded.

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19